A new method for preparing carbon aerogels by using starch as a starting material through sol gel process, followed by supercritical drying and pyrolysis is described. The resulting aerogels which consist of irregular carbon particles with sizes about 20 nm were of uniform sizes, low density, porous monolithic materials with a bulk density of 108 kg·m -3 and an electrical conductivity of 1.6 S·cm -1 . The regular arranging crystal structure in manometer dimensions was observed by using high resolution transmission electron microscopy and electron diffraction. The results of DTA TG studies indicated that when starch aerogels were heated, the carbon aerogels with graphite structure formed through dehydration, pyrolysis and subsequent phase transition. [WT5HZ]
In the water-in-oil mieroemulsion system of Triton X-100, 1-hexanol, cyclohexane and Fe（NO3）3 aqueous solution, α－Fe2O3 ultrafine particles were prepared by the method of precipitation using NH3. From transndssion electron ndcrographs the mean dianreter of particles is about 3nm. The trifornlity of particle is good. These result have been confirmed by the method of Mossbauer spectrum measurement. The conditions of preparation of α－Fe2O3 ultrallne particles could be controlled easily and the reaction medium could be used cyclically.
